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Dyno numbers don't mean anything!

Dyno numbers don't mean anything!

Old 12-20-2003, 09:52 AM
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At last years carpet nats in Milwakee Scott Johnson crushed the track record in qualifying by over a lap,a record that still stands I think.This was with a handout motor he had one day to prepare,and you guessed it it was tuned on a Fantom.
You have to take the time to learn what to look for just like every other dyno out there.
My point is you can use a Fantom to tune motors successfuly if you just spend the time to figure out how the numbers relate to track performance.
If we were racing dynos the Fantom would still win cause its the ONLY one still in production and sold in the US.
With all the guys that think there smarter than the Fantom dyno Im sure atleast one of them could come up with something better at a lower price right???????? Well speak up Im listening!!
Or shut up and go get some track time<geez>
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Old 12-20-2003, 09:56 AM
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/\/\/\/\/\/\/\/\ /\/\/\/\/\/\ HOW TRUE!!!!
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Old 12-20-2003, 11:30 AM
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Yes, good points made, which is why you don't see me saying anything negative about the Fantom(or even the CE Turbo Dyno, for that matter). As I've said in other threads, it's not the dyno itself, as much as it is the guy using it. The biggest factor in deciding if one dyno's numbers are more useful than anothers is just in how easy it is for the USER to understand them. That's the reason why I chose the Robi over the Fantom when I bought mine, I simply had an easier time understanding how the Robi ws getting it's numbers & how it was presenting them to me. But I've had occaisions where I'd get good numbers from a moroe on my Robi, then I'd go to someone I respect(like Troy Schroeder, the owner of Fantom) & ask his opinion on it. And actually, what looked like a good motor to me also did well on HIS dyno & he was pretty pleased with it(& I'm sure we all know what dyno Troy uses, ). But as has been alluded to, the track still IS the MOST important test for any motor, the dynos we use are simply a tool to help point us in the right direction....
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Old 12-20-2003, 01:24 PM
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Seems DynoMoHum knows what he is talking about... here are acouple of posts by Todd Putnam himself, posted on Hobby Talk...

"Pete: It's not even accurate comparing one quad magent vs. another, or one Monster-based stock vs. another. This is why I got away from trusting it in the first place. Too many times we would run a lower performance motor in practice,(according to the Fanton dyno) only to have them outperform the "killer" motors we'd use in racing. When I dug my Turbo Dyno back out and started comparing them on that, it told the true story."

"The only reason we even include the Fantom Facts Machine Max Power, Max Torque, etc. values with our motors is because it has become somewhat of the "industry standard" and consumers want to see it. Do I believe in them, absolutely not."

BigDogRacing wrote....

"Guys this is a perfect example of why you can't always believe or trust everything you read on the forums just because someone seems as if they know what they are talking about"

So is Todd Putnam wrong also?

Last edited by ottoman; 12-20-2003 at 11:32 PM.
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Old 12-21-2003, 12:00 AM
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Yep, I concur with DynoMoHum, although I wouldn't go so far as to call the Fantom Facts Machine worthless. I think for tuning a 1/12th scale motor, or a pan car motor, it is probably just as valuable as any other dyno, as long as the user understands how to use it. However, in 6 cell applications, it is fairly common to have a motor outperform another at 5 volts, but be an entirely different comparison at 7.5 volts.

Obviously the numbers still mean something but in 6 cell applications I wouldn't put as much faith in them as Robitronics or CE TD45 numbers. I think Big Jim thinks the Fantom is easily influenced to produce higher power numbers by higher RPM numbers, and this could be correct, as any many motor's I have dyno'ed on my Robitronics that look good on the Fantom have high RPM figures.
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Old 12-21-2003, 01:53 AM
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Originally posted by SpeediePHATT
The guy who said that dyno numbers dont mean anything dont know what dyno numbers mean.

Even though, if the numbers ARE higher than what a dyno would print out, YOU(the owner of the high numbered motor) will have a mental advantage over someone with the same rated motor. It may not be faster on paper, but if you believe in the numbers, you will mostlikly go faster...

I used to run a Monster(not the Pro version, but the original), which had no numbers. The motor was VERY fast, I guess, because I believed that the motor would make me go faster. My friends droped it onto a dyno, and the numbers that they printed out were very bad. From then on I started to worry that people were pulling me down the straight and I felt as though the motor slowed...

Suposedly R/C Racing is 80-85% mental...

Do you agree?...
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Old 12-21-2003, 07:18 AM
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No I don't agree at all...I think it is closer to 95% Mental!Did you know that when factory riders test new engines for Superbike and MotoGP racing, the techs WILL NOT tell the rider's how much torque or HP the new engine is making?
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Old 12-21-2003, 07:31 AM
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Who am I? I am a average racer that has spent more time playing with motors and dynos over the last 3 years then I probably should have if I wanted to be really fast on the track. I'm primarly a oval racer who current runs 4 cell 19 turn class. If I tired to run full mod I'd get in everyones way and make nothing but enemys on the track. I'm a electronic technician with 18 years of experiance with electronic test equipment and such. I have a very analitical mind if I do say so myself, and I can't spell worth a crap.

I didn't reall mean to imply that the Fantom is worthless, although I did fully intend to state that it's data is highly suspect by many reputable people, some of whom are much more reputable then I am in the RC word. When I used the word 'worthless' pervioulsy, I meant that Trinity's lables on their "pro" motors are worthless. Not simply because the data came from a Fantom, but also becuse the brushes are not fully seated when the tests are proformed. That last aspect is worse then the data the Fantom produces itself.

My understading is that EPIC now makes statements that would indicate they don't even trust the fantom data they get. I don't have the exact quotes but they basicly imply that their new motor runs better on the track then it does on the dyno.

As otman has pointed out, Todd Putnam himself has recently made several statements that he does not trust Fantom data, and that he hasn't for quite some time. His recent statments were directly related to what he's seen of the EPIC Binary 2 'outlaw' on the Fantom and on the Track. The short discription of what he's said... The Fantom can't be trusted and the EPIC does run well on the track, regardless of what the Fantom may or may not tell you.

Besides Todd's comments, and even EPIC's recent staments... I have done alot of my own testing, and quite frankly the Fantom's numbers just don't seem to be accurate.

I have no doubts that many a fast guy with a Fantom will consider my opion just a bunch of hooey, and that many a fast Fantom user really can tune a motor quite well, and ceritianly many a Fantom user can go fast on the track... I also have NO doubt that if any of these guys sat down with me and my dyno for several hours, I could show them why I think they could find out how to be even faster if they used something other then a Fantom.

I'll never be a really fast racer, I just don't think it's in me...I'm 42 now, and I think it's a little to late to develop the skills needed to go fast on the track. However, I can tell you that my opions about the Fantom being suspect have nothing to do with my driving ablity. I can also tell you that the reason I'm not fast on the track, has nothing to do with my motor's ablity to go fast.

Last edited by DynoMoHum; 12-21-2003 at 08:47 AM.
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Old 12-22-2003, 12:37 PM
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My basic opion is that amp draw with no load at low voltage doesn't really mean that much, perticularly when the brushes aren't fully broken in yet. This is another thing that I've disagreed with many people on, as there are alot of people that are convicned that the more amp draw the better on most any motor. Recently Todd Putnam has also made comments that tend to agree with my opion that amp draw doesn't mean much...

I'm not saying Todd is the worlds greatest motor man, but by most accounts he is highly respected, and certianly much more deserving of respect for motor knowlege then I am. So when he makes statments that agree with my opion, I sit up and take notice.

Here is another recent quote from Todd Putnam over on HobbyTalk's oval section...

"Amp draw doesn't directly equate to power... In fact, it can have the opposite effect. Excessive amp draw can result in increased heat and increased battery consumption. A motor that runs hotter and uses more battery may not finish as strong as a motor that is running cooler and isn't as far down the battery's voltage curve.
In the classes where runtime is an issue, if you increase your energy consumption by a greater percentge than the horsepower you get in return, you will typically be slower overall...even though your motor is creating more horsepower. There are exceptions to the rule, of course..."
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Old 12-22-2003, 01:53 PM
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OK here's my .02 cents.
I think the reason why people dont like the fantom dyno is because it give you a power reading that can be HIGHLY influenced by the RPM. If you go into the time-base and look at 1 second and 1.8 seconds that will tell the tale. it will explain why some motors dyno awesome and run like chit or dyno bad and run awesome. I have a little experience in motor tuning myself and the fantom dyno can be very useful. also with gearing. I tuned motors in cleveland for the us indoor champs for myself-1/12 scale stock TQ, Alex Lopez-stock sedan 1st place, Eli Ezro-sedan masters TQ,Rob Love sedan A main, and many others,and I tuned them with the fantom dyno, also was able to give these guys the gear they needed to run to make the motor work the best. I think all dynos are really beneficial in these aspects.I cant say one dyno is better than the other it just matters if someone can figure it out or not.and as far as amp draw goes, I never go by amp draw, an improperly built motor can pull alot of mysterious amps, brush bounce,vibration,messed up bushings all kinds of wrong things can create amp draw. I have to agree with what was said earlier about the numbers on the motors in the hobby shops are good for comparing only motors of the same make,tuner and manufacturer.
Fukuyama has a motor line coming out and I think you guys might be suprised.
the other thing to consider is that what are they powering the dyno with, power supply,gell cell, car battery, six cells. all these things also make a difference.
again just my .02 cents
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Old 12-22-2003, 06:51 PM
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ok im new to this electric stuff so please pardon my ignorance

if i buy a motor with a high power rating on its label how likely is it that motor will be better than another with the same label?

if i then take that motor and run it at 2v for 200 seconds and read amp draw lets say its 7.5-8amps

then next time i rebuild it and change brushes and springs and now the same motor pulls 9.5-10amps

is it fair to say my changes have had a positive effect?

i didnt know much about electric motors and i definetly dont have dyno access so i picked the best chameleon motors i could find by the power rating on their labels

then i went online and found threads where guys were talking about these motors and tried what they said worked and i had the senario i wrote above
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Old 12-22-2003, 08:18 PM
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So no-one owns a CS dyno?

In relation to the readings supplied using the CS Dyno one of the three areas is max output. Within this area the read out identifies both Amps and Nmm. Are higher readings for each of these two areas positives or negatives?
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Old 12-22-2003, 09:45 PM
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PTP Racing - I don't trust most company's numbers they put on the labels one bit, but if I was buying a stock motor I'd still go for the one with the highest numbers.

I tend to use 2.5 volts, and I find that with a stock motor, anything higher than 9 amps will burn up brushes and comms faster. I like to have my motors have fairly low numbers on my T35 for this reason, but that's just how I do it. I know alot of people with and without dyno's who try to achieve the highest amp draws they can, but without a load it seems rather pointless to me.

The best way for you to determine if your changes had a positive effect would be to just take the motor out on the track. If it feels faster, then I'd say they did.

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Old 12-23-2003, 09:27 AM
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Nice post Mo... I must say that I'm sure that if I spent enought time with a Fantom, I too beleive that one way or another I could figure out how to use it's data to help me make a motor run faster. Clearly you and others have found ways to use the Fantom, and you have done a excelent job at explaining how you do it.

You are also right that most of us who have doubts about the Fantom data, have it because it does seem to be highly dependant on RPM. Previously most of us had thought that it seemed the more RPM the more the Fantom would like the motor, now with the Bin2 'outlaw' it seems the Fantom's peak power numbers don't look good even though it has MORE RPM... so this now seems to indicate that there is some pertucular RPM range that it favors... which adds another wrinkle to the Fantom saga... One question I have still is... If the peak power numbers are off, then how could one be sure that all other numbers are not off? Anway... I continue to have my own personal doubts about the Fantom data... but as I said previoulsy... i also know that many people are able to make use of it's data in spite of what my opion is about it...

My ohter comments about other posts I'll put in a nother post of my own...
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Old 12-23-2003, 09:50 AM
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CS dyno... I don't own one, but I am somewhat firmilar with it's data... It is simmilar to Robitronic data, that I am very firmailar with, since that is the dyno I use.

Nmm are a metric measurment of Torque, Power is basicly made up of Torque and RPM both... If a motor that has 100 watts of power, at 3,000 RPM, it will have some specific value of torque. If another motor has 100 watts of power at 4000 RPM, it will have a lower value for Torque at that point... there is no changing this fact... It's all physics and such... the more RPM at any given power, the lower the Torque must be... So, really the amount of Torque is somewhat insignificant... Why? becase gearing takes care of differnt RPM and Torque values.... POWER allows you to sort of forget about Torque/RPM untill it comes time to gear the motor... (I'm not going to go into gearing at this time however)

Amp numbers... at peak power (or elsewhere), are are sort of like fuel consumption in a combustion engine... The more current (Amps) it takes to produce a given amount of output power (watts), the less effcienent the motor is... (this assumes that the voltage input is the same)... Without giving a short course in electronics... Don't bee too concerned about amp input for now... Look at effciency numbers if you really want to know what the Effciency is... (output/input = effciency)

I'll say it once again.... AMP numbers at low voltages with no load on the motor... are not all that usefull in determining the proformance of a motor... At least not without knowing a lot of other stuff to go with that bit of information. I'll give you a couple examples of why I say this, the first is a bit extreeme but important... The second is a bit more realistic of what you might see that could confuse you...

First... go wedge a e-clip inbetween the armature and the magnets of one of your motors, apply 2 volts and see the amp draw go to the moon... (I said it was extreeme) Ok, so don't do that, it's stupid... but think about what would happen if something in your bushings was causing your motor to have some binding, your amp will go up, and your proformance will go down.

Second.... A full faced laydown brush on a standard size commutator has what is known as 'overlap'. Overlap causes dead shorting between the brushes across a comm segment 6 times per revolution of the motor, this will also cause AMP input to go higher. (a dead short has less resistance then a winding on one of the armature segments less resistance leads to more current, it's all OHM's law and basic electornics) This overlap typical causes lower effciency in many motors, some overlap can be helpfull but too much can indeed be harmfull to the proformance of a motor. Typicaly if you trim a lay down brush by say .010" the motor will run more effcienctly then if you don't trim the brush. A motor with a full faced brush, will draw more no load current then a motor with a trimed brush, but it typicaly won't produce more power output.... Sometimes triming laydown bursh more then .010" will work even beter, and produce less no load amp consumption... but not always...

my basic stament about no load amp draw... 'BY ITSELF, it means very little'.
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